var assert = require("assert")
describe('Array', function(){
    describe('#indexOf()', function(){
        it('should return -1 when the value is not present', function(){
            assert.equal(-1, [1,2,3].indexOf(5));//成功
            assert.equal(-1, [1,2,3].indexOf(1));//失败，因为表达式为：-1==0
        })
    })
});